Electrophotographic photoreceptor, method for manufacturing an electrophotographic photoreceptor, process cartridge, and electrophotographic apparatus

Abstract

The present invention provides an electrophotographic photoreceptor having an undercoat containing an electron-transporting compound that prevents interference fringes from being observed on halftone images and reduces image white spots caused by electrical degradation when repeatedly printed over long periods in a low-humidity environment. [Solution] An electrophotographic photoreceptor that reduces the number of protrusions by controlling the surface roughness of the undercoat layer as follows, where Rz is the maximum height, Rc is the average height, and RSm is the average length of the roughness curve specified in JIS B 0601:2001. 0.3 μm ≤ Rz ≤ 1.0 μm Rc / Rz ≥ 70% 0.17mm ≤ RSm ≤ 0.35mm

Description

[Technical Field]

[0001] The present invention relates to an electrophotographic photoreceptor, a process cartridge having the electrophotographic photoreceptor, an electrophotographic apparatus having the electrophotographic photoreceptor, and a method for manufacturing an electrophotographic photoreceptor. [Background technology]

[0002] Electrophotographic photoreceptors (hereinafter also referred to as "photoreceptors") mounted in process cartridges and electrophotographic devices generally have a conductive cylindrical support and a photosensitive layer formed on the support. In order to suppress charge injection from the support to the photosensitive layer, thereby reducing the occurrence of image defects and improving leakage resistance, an undercoat layer is often provided between the support and the photosensitive layer. For example, Patent Document 1 describes an electrophotographic photoreceptor using a material containing an electron-transporting compound of a specific structure in the undercoat layer.

[0003] Incidentally, when an electrophotographic photoreceptor is exposed to coherent light such as a semiconductor laser, interference fringes may appear in the formed toner image, and density unevenness may occur in the halftone image. One reason for this is that the exposure light is not completely absorbed within the photosensitive layer, and the transmitted light is specularly reflected off the surface of the undercoat layer, causing interference between this reflected light and the reflected light from the surface of the photosensitive layer.

[0004] To address the above problem, methods for improving the undercoat have been proposed. For example, Patent Document 2 proposes forming an undercoat with a coating liquid in which conductive metal oxide particles are dispersed, thereby creating irregularities on the surface of the undercoat and suppressing interference fringes. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-46640 [Patent Document 2] Japanese Patent Publication No. 2005-275395 [Overview of the project] [Problems that the invention aims to solve]

[0006] According to the inventors' research, an electrophotographic photoreceptor having an undercoat containing an electron-transporting compound as described in Patent Document 1 exhibits a higher ability to suppress charge injection from the support side to the photosensitive layer compared to an undercoat using conductive ions or metal oxide particles. However, it tends to degrade in conductivity when repeatedly printed over long periods in a low-humidity environment. When degradation occurs, white spots, which are image defects, may appear in the output image, indicating that there is room for improvement.

[0007] Therefore, the object of the present invention is to provide an electrophotographic photoreceptor having an undercoat containing an electron-transporting compound that does not show interference fringes on halftone images and reduces image white spots caused by electrical degradation when repeatedly printed over a long period of time in a low-humidity environment. [Means for solving the problem]

[0008] The above objective is achieved by the present invention as follows. That is, an electrophotographic photoreceptor according to one aspect of the present invention has a cylindrical support, an undercoat formed directly on the support, and a photosensitive layer formed directly on the undercoat, wherein the undercoat contains a cured product of a composition containing an electron transport compound, and when the maximum height of the roughness curve of the surface of the undercoat in the generatrix direction of the support, as defined in JIS B 0601:2001, is Rz, the average height is Rc, and the average length is RSm, 0.3 μm ≤ Rz ≤ 1.0 μm Rc / Rz ≥ 70% 0.17mm ≤ RSm ≤ 0.35mm It is characterized by satisfying the following conditions.

[0009] Further, a method for producing an electrophotographic photoreceptor according to another aspect of the present invention is a method for producing an electrophotographic photoreceptor comprising a cylindrical support, an undercoat layer formed directly on the support, and a photosensitive layer formed directly on the undercoat layer, the method comprising: a step of cutting the surface of the support; and a step of applying, directly on the support, a liquid containing a cured product of a composition including an electron-transporting compound to form a coating film, wherein when Rz represents the maximum height of a roughness curve defined in JIS B 0601:2001, Rc represents the average height, and RSm represents the average length of the roughness curve in the generatrix direction of the support on the surface of the undercoat layer, 0.3μm≦Rz≦1.0μm Rc / Rz≧70% 0.17mm≦RSm≦0.35mm the method comprises a forming step of forming the undercoat layer having a shape satisfying the above conditions.

[0010] Further, a process cartridge according to another aspect of the present invention is characterized in that it integrally supports the electrophotographic photoreceptor described above and at least one means selected from the group consisting of a charging means, a developing means, and a cleaning means, and is detachably attachable to a main body of an electrophotographic apparatus.

[0011] Further, an electrophotographic apparatus according to still another aspect of the present invention is characterized by comprising the electrophotographic photoreceptor described above, and a charging means, an exposing means, a developing means, and a transferring means. Effects of the Invention

[0012] According to the present invention, there can be provided an electrophotographic photoreceptor having an undercoat layer containing an electron-transporting compound, in which no interference fringes are observed on a halftone image, and white spot defects in an image caused by conduction deterioration when repeated printing is performed for a long period of time in a low-humidity environment are reduced. Brief Description of Drawings

[0013] [Figure 1] FIG. 1 is a schematic cross-sectional view showing the layer structure of the electrophotographic photoreceptor according to the present invention. [Figure 2(a)] FIG. 2 is a schematic cross-sectional view showing unevenness on the surface of the undercoat layer. [Figure 2(b)]It is a schematic cross-sectional view showing unevenness on the surface of an undercoat layer. [Figure 3] It is a schematic cross-sectional view showing an example of a schematic configuration of an electrophotographic apparatus having a process cartridge including an electrophotographic photosensitive member. [Figure 4] It is a schematic diagram showing measurement positions for surface roughness measurement and spectral spectrum measurement. MODE FOR CARRYING OUT THE INVENTION

[0014] The present invention relates to an electrophotographic photosensitive member. The electrophotographic photosensitive member of the present invention includes a cylindrical support, an undercoat layer formed directly on the support, and a photosensitive layer formed directly on the undercoat layer, and is an electrophotographic photosensitive member in which the undercoat layer contains a cured product of a composition containing an electron-transporting compound. When, in the generatrix direction of the support, the maximum height of the roughness curve defined in JIS B 0601:2001 on the surface of the undercoat layer is Rz, the average height is Rc, and the average length is Rsm, 0.3 μm ≦ Rz ≦ 1.0 μm Rc / Rz ≧ 70% 0.17 mm ≦ RSm ≦ 0.35 mm characterized by satisfying Hereinafter, the present invention will be described in detail with reference to preferred embodiments.

[0015] The electrophotographic photosensitive member of the present invention includes a support, an undercoat layer formed directly on the support, and a photosensitive layer formed directly on the undercoat layer. The electrophotographic photosensitive member 100 shown in FIG. 1 is formed by laminating an undercoat layer 103 on a surface 102 of a support 101, and a photosensitive layer 105 (including a charge generation layer 106 and a charge transport layer 107) on a surface 104 of the undercoat layer.

[0016] When such an electrophotographic photoreceptor 100 is used in an electrophotographic apparatus that uses a coherent light source, interference may occur between the incident light and the reflected light at each layer interface when the surface 108 of the electrophotographic photoreceptor 100 is exposed. As a result, the potential of the surface 108 of the electrophotographic photoreceptor 100 becomes non-uniform, and when the latent image of the electrophotographic photoreceptor 100 is developed to form an image, it appears as interference fringes. This phenomenon is particularly noticeable when forming halftone images.

[0017] In order to suppress interference fringes by causing diffuse reflection of the light reflected from the surface 104 of the undercoat layer 103, it has been conventionally practiced to form irregularities on the surface 104 with a height of about 0.3 to 3 μm at intervals of about 30 to 100 μm.

[0018] However, when an electrophotographic photoreceptor containing a cured product of an electron-transporting compound in the undercoat, with irregularities formed on the surface of the undercoat at intervals of several tens of micrometers, was repeatedly printed over a long period in a low-humidity environment, image defects such as halftone images or white spots on solid images sometimes occurred. It is thought that repeated printing over a long period in a low-humidity environment causes a larger current to flow through the photoreceptor compared to other environments, leading to electrical degradation of the undercoat.

[0019] Regarding the degradation of the electrical conductivity of the lower layer, the inventors speculate that conditions that make it prone to degradation include the fact that the electron-transporting compound is organic, that current flows more easily at the protrusions than at other locations, that the protrusions are tall, and that the spacing between the bumps is narrow and the number of protrusions is large.

[0020] Figure 2 is a schematic cross-sectional view showing the surface irregularities of the undercoat layer. Figure 2(a) shows a surface with narrow spacing between irregularities, and Figure 2(b) shows a surface with wide spacing between irregularities. When the spacing between irregularities is narrow, the number of protrusions increases. Therefore, to achieve the objective, we believe that the number of protrusions in the easily degraded undercoat layer should be reduced, that is, the average length RSm of the roughness curve, which represents the spacing between irregularities in the undercoat layer, should be made as wide as possible. However, if the average length RSm is made too wide, the slope of the irregularities becomes gentler and the surface becomes nearly flat, and a sufficient interference fringe suppression effect may not be obtained.

[0021] Furthermore, if the height of the irregularities is too low, sufficient interference fringe suppression may not be achieved, and if it is too high, the effect of suppressing the deterioration of electrical conductivity in the underlying layer may not be achieved. Therefore, the height of the irregularities needs to be within an appropriate range. Moreover, it is better if the variation in height is small.

[0022] As a result of diligent research conducted by the inventors, when the maximum height of the roughness curve specified in JIS B 0601:2001 for the surface of the under-drawn layer in the generatrix direction of the support is Rz, the average height is Rc, and the average length is RSm, 0.3 μm ≤ Rz ≤ 1.0 μm Rc / Rz ≥ 70% 0.17mm ≤ RSm ≤ 0.35mm By satisfying these conditions, the present invention reduces white spots in the image by suppressing interference fringes in halftone images while suppressing the degradation of the undercoat layer's conductivity. Regarding Rc / Rz (average / maximum surface unevenness), a higher value indicates smaller variation in surface unevenness, with a value of 70% or higher indicating very small variation and generally uniform surface unevenness.

[0023] The average length RSm has a lower limit of 0.17 mm or more, but is preferably 0.20 mm or more. The upper limit is usually 0.35 mm or less, but is preferably 0.34 mm or less, and more preferably 0.30 mm or less.

[0024] [Electrophotographic photoconductor] The electrophotographic photoreceptor of the present invention comprises a support, an undercoat formed directly above the support, and a photosensitive layer formed on the undercoat. The support is preferably cylindrical. The photosensitive layer is preferably composed of a charge generation layer formed on the undercoat and a hole transport layer formed on the charge generation layer.

[0025] A method for manufacturing the electrophotographic photoreceptor of the present invention includes preparing coating solutions for each layer described later, forming coating films of the coating solutions, and drying and / or curing the coating films. Examples of coating methods (methods for forming the coating films) include blade coating, curtain coating, wire bar coating, and ring coating. Among these, immersion coating is preferred from the viewpoint of efficiency and productivity.

[0026] The support structure and each layer will be described below. <Support material and its manufacturing method> The method for manufacturing the support is not particularly limited, as long as it is a method that can manufacture a support that satisfies the requirements of the present invention. The support is preferably cylindrical. Furthermore, the support is preferably made of an aluminum alloy. One example of a method for manufacturing a support is a method that includes the following steps:

[0027] First, the aforementioned aluminum alloy is prepared. A molded body is obtained by hot extrusion. The obtained molded body is then subjected to cold drawing. After that, it is cut to the desired dimensions to produce a raw pipe.

[0028] Furthermore, if necessary, the surface (outer surface) of the raw tube is machined on a lathe to obtain a support. The surface shape of the support can be continuously formed in the circumferential direction by adjusting the shape and type of cutting tool used and the feed pitch of the tool. The shape of the cutting tool refers to the shape of the cutting edge, such as an R shape or a flat shape. The type of cutting tool refers to the material of the cutting edge, such as single-crystal diamond or polycrystalline diamond. In the case of polycrystalline diamond, it is necessary to appropriately select the average particle size of the diamond. The feed pitch of the cutting tool refers to the amount of feed the tool is moved per revolution of the lathe.

[0029] When forming the coating film on the electrophotographic photoreceptor of the present invention by immersion coating, if irregularities are formed on the support at regular intervals in the direction of the generatrix (the direction of lifting) when the support is pulled out of the immersion coating solution, the coating film will also form irregularities that reflect the irregularities of the support to some extent. This makes it relatively easy to adjust the spacing and height of the irregularities on the surface of the undercoat layer to a desired range, and it is also possible to reduce the variation in the height of the irregularities. Therefore, it is preferable to machine the surface of the support of the present invention in order to form appropriate irregularities.

[0030] <Underlayer> In the present invention, by providing an undercoat layer directly above the support, the interlayer adhesion function is enhanced, a charge injection prevention function is provided, and leak resistance is improved. Furthermore, the undercoat contains electron-transporting compounds to enhance its electrical properties.

[0031] Examples of electron-transporting compounds include quinone compounds, imide compounds, benzimidazole compounds, cyclopentadienylidene compounds, fluorenone compounds, xanthone compounds, benzophenone compounds, cyanovinyl compounds, aryl halides, silole compounds, and boron-containing compounds. An electron-transporting compound having a polymerizable functional group may be used as the electron-transporting compound, and copolymerized with the above-mentioned monomer having a polymerizable functional group to form a cured film undercoat. In the present invention, the undercoat layer is formed directly on the support and preferably contains a cured product of a composition comprising an electron-transporting compound represented by formula (A1) or an electron-transporting compound represented by formula (A2). Having an electron-transporting compound represented by formula (A1) or an electron-transporting compound represented by formula (A2) makes it possible to ensure excellent electron transport properties. [ka] (In formulas (A1) and (A2), R 101 ~R 106 , R 201 ~R 210Each of these independently represents a monovalent group, a hydrogen atom, a cyano group, a nitro group, a halogen atom, an alkoxycarbonyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group represented by the following formula (B). However, R 101 ~R 106 At least one of the following, and R 201 ~R 210 At least one of the groups is a monovalent group represented by the following formula (B). One of the CH2 groups of the alkyl group may be substituted with O or S, or one of the CH groups of the alkyl group may be substituted with N. The substituent of the substituted alkyl group is at least one group selected from the group consisting of aryl groups, alkoxycarbonyl groups, halogen atoms, and hydroxyl groups. The substituent of the substituted aryl group and the substituted heterocycle is at least one group selected from the group consisting of halogen atoms, nitro groups, cyano groups, alkyl groups, halogen-substituted alkyl groups, and alkoxy groups. [ka] (In formula (B), at least one of a, b, and c has at least one group selected from the group consisting of a hydroxyl group, a thiol group, an amino group, and a carboxyl group. l and m are each independently 0 or 1, and the sum of l and m is between 0 and 2.)

[0032] a represents an alkylene group having 1 to 6 carbon atoms in the main chain, an alkylene group having 1 to 6 carbon atoms in the main chain substituted with an alkyl group having 1 to 6 carbon atoms, an alkylene group having 1 to 6 carbon atoms in the main chain substituted with a benzyl group, an alkylene group having 1 to 6 carbon atoms in the main chain substituted with an alkylocarbonyl group, or an alkylene group having 1 to 6 carbon atoms in the main chain substituted with a phenyl group. These alkylene groups may have at least one substituent selected from the group consisting of a hydroxyl group, a thiol group, an amino group, and a carboxyl group. One of the CH2s in the main chain of these alkylene groups may be substituted with O or S, or one of the CHs in the main chain of these alkylene groups may be substituted with N.

[0033] b represents a phenylene group, a C1-C6 alkyl-substituted phenylene group, a nitro-substituted phenylene group, a halogen-substituted phenylene group, or an alkoxy-substituted phenylene group, and these phenylene groups may have at least one substituent selected from the group consisting of a hydroxyl group, a thiol group, an amino group, and a carboxyl group.

[0034] c represents a hydrogen atom, a carboxyl group, an alkyl group with 1 to 6 carbon atoms in the main chain, or an alkyl group with 1 to 6 carbon atoms in the main chain substituted with an alkyl group with 1 to 5 carbon atoms. These alkyl groups may have at least one substituent selected from the group consisting of a hydroxyl group, a thiol group, an amino group, and a carboxyl group.

[0035] Furthermore, the electron transport compound selected from the group consisting of the electron transport compound represented by formula (A1) and the electron transport compound represented by formula (A2) may be used alone or in combination of two or more.

[0036] (Regarding electron-transporting compounds represented by formula (A1) and formula (A2)) The electron-transporting compounds represented by formula (A1) and formula (A2) are shown in Tables 1-1 to 1-7 below. Compounds (A101) to (A168) are specific examples of electron-transporting compounds represented by formula (A1), and compounds (A201) to (A231) are specific examples of electron-transporting compounds represented by formula (A2). In Tables 1-1 to 1-7, when "(H)" is written for c, it indicates that c is a hydrogen atom in the structure shown in column a or b, and the structure of formula (B) is the structure shown in column a or b. When column a or b is (-), it indicates that l or m is 0.

[0037] The following are specific examples, and the effects of the present invention are not limited to these examples. These compounds may be used individually or in combination.

[0038] [Table 1-1]

[0039] [Table 1-2]

[0040] [Table 1-3]

[0041] [Table 1-4]

[0042] [Table 1-5]

[0043] [Table 1-6]

[0044] [Table 1-7]

[0045] The structure of the monovalent group represented by formula (B) in the table above can be described as follows. In other words, the monovalent group represented by formula (B) is an alkyl group having 1 to 12 carbon atoms, a phenyl group, or a phenylalkyl group having 6 to 12 carbon atoms, all of which may have substituents. However, the substituents that the alkyl group having 1 to 12 carbon atoms may have are any of the following: a hydroxyl group, a thiol group, an amino group, a carboxyl group, an alkoxycarbonyl group, or an alkoxy group. The substituents that the phenyl group or the phenylalkyl group having 6 to 12 carbon atoms may have are a methyl group, an ethyl group, a hydroxymethyl group, a hydroxyethyl group, a carboxymethyl group, a carboxyethyl group, a hydroxy group, a thiol group, an amino group, a carboxy group, and an alkoxycarbonyl group. In the alkyl group having 1 to 12 carbon atoms or the alkyl group contained in the phenylalkyl group having 6 to 12 carbon atoms, one CH₂ may be substituted with O or S, or one CH may be substituted with N. Provided that the monovalent group represented by formula (B) contains any one of a hydroxy group, a thiol group, an amino group, or a carboxy group.

[0046] It is also preferable that the undercoat layer according to the present invention contains a compound represented by the following formula (α).

Chemical Formula

[0047] Specific examples of the compound (α) represented by formula (α) are shown in Table 2-1 below.

Table 2-1

[0048] The undercoat layer according to the present invention can be formed as a cured film by polymerizing a composition containing the above compound and a monomer having a polymerizable functional group.

[0049] Polymerizable functional groups found in monomers possessing polymerizable functional groups include isocyanate groups, blocked isocyanate groups, methylol groups, alkylated methylol groups, epoxy groups, metal alkoxide groups, hydroxyl groups, amino groups, carboxyl groups, thiol groups, carboxylic acid anhydride groups, and carbon-carbon double bond groups. The resins that may be included are polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, epoxy resin, melamine resin, polyurethane resin, phenolic resin, polyvinylphenol resin, alkyd resin, polyvinyl alcohol resin, polyethylene oxide resin, polypropylene oxide resin, polyamide resin, polyamic acid resin, polyimide resin, polyamideimide resin, cellulose resin, and the like.

[0050] The undercoat layer may contain metal oxide particles, metal particles, conductive polymers, etc., for the purpose of improving electrical properties. Examples of metal oxides include indium tin oxide, tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, and silicon dioxide. Examples of metals include gold, silver, and aluminum. However, when a base coat is applied using a coating solution containing dispersed particulate metal oxides, depending on the amount of particles, irregularities may be formed on the surface of the base coat. Furthermore, if the amount of particles is large, the number of irregularities increases, and the spacing between them narrows, which may prevent the electrical conductivity degradation suppression effect from being obtained. Therefore, when metal oxide particles are included, it is preferable that the content of metal oxide particles relative to the total solid content of the base coat is 1.0% by mass or less. More preferably, it is preferable that the base coat does not contain metal oxide particles. Furthermore, the underlayer may contain additional additives.

[0051] To more efficiently obtain the effects of the present invention, the thickness of the undercoat layer is preferably 0.5 μm or more and 2.5 μm or less.

[0052] The undercoat can be formed by preparing an undercoat coating solution containing the above-mentioned materials and solvents, forming a coating film, and then drying and / or curing it. Examples of solvents used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0053] <Photosensitive layer> The photosensitive layers of electrophotographic photoreceptors are mainly classified into (1) multilayer photosensitive layers and (2) single-layer photosensitive layers. (1) A multilayer photosensitive layer has a charge generating layer containing a charge generating material and a charge transport layer (hole transport layer) containing a charge transport material. (2) A single-layer photosensitive layer is a photosensitive layer that contains both a charge generating material and a charge transport material.

[0054] (1) Stacked photosensitive layer The stacked photosensitive layer comprises a charge generation layer and a charge transport layer.

[0055] (1-1) Charge generation layer The charge generation layer preferably contains a charge-generating substance and a resin (binding resin). Examples of charge-generating materials include azo pigments, perylene pigments, polycyclic quinone pigments, indigo pigments, and phthalocyanine pigments. Among these, azo pigments and phthalocyanine pigments are preferred. Among phthalocyanine pigments, oxytitanium phthalocyanine pigments, chlorogallium phthalocyanine pigments, and hydroxygallium phthalocyanine pigments are preferred.

[0056] The content of the charge generating material in the charge generating layer is preferably 40% to 85% by mass, and more preferably 60% to 80% by mass, relative to the total mass of the charge generating layer.

[0057] Examples of resins include polyester resin, polycarbonate resin, polyvinyl acetal resin, polyvinyl butyral resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenolic resin, polyvinyl alcohol resin, cellulose resin, polystyrene resin, polyvinyl acetate resin, and polyvinyl chloride resin. Among these, polyvinyl butyral resin is preferred.

[0058] Furthermore, the charge generation layer may contain additives such as antioxidants and ultraviolet absorbers. Specifically, examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, and benzophenone compounds.

[0059] The thickness of the charge generation layer is preferably 0.1 μm or more and 1 μm or less, and more preferably 0.15 μm or more and 0.4 μm or less.

[0060] The charge generation layer can be formed by preparing a coating solution for the charge generation layer containing the above-mentioned materials and solvents, forming a coating film of the coating solution, and drying the coating film. Examples of solvents used in the coating solution for the charge generation layer include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0061] (1-2) Charge transport layer The charge transport layer preferably contains a charge transport material and a resin (binding resin). Examples of charge transport materials include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these substances. Among these, triarylamine compounds and benzidine compounds are preferred. The content of the charge transport material in the charge transport layer is preferably 25% by mass or more and 70% by mass or less, and more preferably 30% by mass or more and 55% by mass or less, based on the total mass of the charge transport layer.

[0062] Examples of resins include polyester resin, polycarbonate resin, acrylic resin, and polystyrene resin. Among these, polycarbonate resin and polyester resin are preferred. Polyarylate resin is particularly preferred among polyester resins. The ratio of charge transport material to resin in the charge transport layer (mass ratio, charge transport material:resin) is preferably 4:10 to 20:10, and more preferably 5:10 to 12:10.

[0063] The charge transport layer may contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, lubrication agents, and wear resistance enhancers. Specifically, examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, and boron nitride particles.

[0064] The thickness of the charge transport layer is preferably 5 μm to 50 μm, more preferably 8 μm to 40 μm, and particularly preferably 10 μm to 30 μm.

[0065] The charge transport layer can be formed by preparing a coating solution for the charge transport layer containing the above-mentioned materials and solvents, forming a coating film of the coating solution, and drying the coating film. Examples of solvents used in the coating solution for the charge transport layer include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Among these solvents, ether-based solvents and aromatic hydrocarbon-based solvents are preferred.

[0066] <Protective layer> In this invention, a protective layer may be provided on the photosensitive layer. Providing a protective layer can improve durability. The protective layer preferably contains conductive particles and / or charge transport material and resin.

[0067] Examples of conductive particles include metal oxide particles and metal particles. Examples of metal oxides include titanium oxide, zinc oxide, tin oxide, and indium oxide.

[0068] Examples of charge transport materials include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these substances. Among these, triarylamine compounds and benzidine compounds are preferred.

[0069] Examples of resins include polyester resin, acrylic resin, phenoxy resin, polycarbonate resin, polystyrene resin, phenolic resin, melamine resin, and epoxy resin. Among these, polycarbonate resin, polyester resin, and acrylic resin are preferred.

[0070] The protective layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group. Examples of polymerization reactions include thermal polymerization, photopolymerization, and radiation polymerization. Examples of polymerizable functional groups in the monomer include acryloyl groups and methacryloyl groups. Compounds with charge transport ability may also be used as the monomer having a polymerizable functional group.

[0071] The protective layer may contain additives such as antioxidants, UV absorbers, plasticizers, leveling agents, lubrication agents, and wear resistance enhancers. Specifically, examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, and boron nitride particles.

[0072] The thickness of the protective layer is preferably 0.5 μm to 10 μm, and more preferably 1 μm to 7 μm.

[0073] A protective layer can be formed by preparing a protective coating solution containing the above-mentioned materials and solvents, forming a coating film of the protective coating solution, and drying and / or curing the coating film. Examples of solvents used in the protective coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, sulfoxide-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0074] [Process cartridges, electrophotographic equipment] The process cartridge of the present invention is characterized in that it integrally supports the electrophotographic photoreceptor described above and at least one means selected from the group consisting of a charging means, a developing means, and a cleaning means, and is detachably attached to the electrophotographic apparatus body.

[0075] The electrophotographic apparatus of the present invention is characterized by comprising the above-mentioned electrophotographic photoreceptor, as well as a charging means, an exposure means, a developing means, and a transfer means.

[0076] Figure 3 shows an example of a schematic configuration of an electrophotographic apparatus having a process cartridge equipped with an electrophotographic photoreceptor.

[0077] The cylindrical electrophotographic photoreceptor 301 is rotated at a predetermined peripheral speed in the direction of the arrow around the axis 302. The surface of the electrophotographic photoreceptor 301 is charged to a predetermined positive or negative potential by the charging means 303.

[0078] Figure 3 shows a roller charging method using a roller-type charging member (charging roller), but other charging methods such as corona charging, proximity charging, and injection charging may also be used.

[0079] Exposure light 304 is shone onto the surface of the charged electrophotographic photoreceptor 301 from an exposure means (not shown), forming an electrostatic latent image corresponding to the desired image information. The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 301 is developed with toner contained in the developing means 305, forming a toner image on the surface of the electrophotographic photoreceptor 301. The toner image formed on the surface of the electrophotographic photoreceptor 301 is transferred to a transfer material 307 by a transfer means 306. The transfer material 307 with the transferred toner image is transported to a fixing means 308, where the toner image is fixed and printed out to the outside of the electrophotographic device.

[0080] The electrophotographic apparatus may have a cleaning means 309 for removing toner and other deposits remaining on the surface of the electrophotographic photoreceptor 301 after transfer. Alternatively, a so-called cleanerless system may be used in which the deposits are removed by a developing means 305 or the like, without a separate cleaning means 309.

[0081] The electrophotographic apparatus may have a static elimination mechanism that removes static electricity from the surface of the electrophotographic photoreceptor 301 using pre-exposure light 310 from a pre-exposure means (not shown). Furthermore, a guide means 312, such as a rail, may be provided for attaching and detaching the process cartridge 311 of the present invention to the main body of the electrophotographic apparatus.

[0082] The electrophotographic photoreceptor of the present invention can be used in laser beam printers, LED printers, copiers, facsimile machines, and multifunction devices thereof. [Examples]

[0083] The present invention will be described in more detail below using examples and comparative examples. The present invention is not limited in any way by the following examples, unless it exceeds the gist of the invention. In the following examples, "parts" refers to mass unless otherwise specified.

[0084] <Manufacturing of support structures> The surface of a cylindrical tube made of aluminum alloy (JIS-A3003) was machined using a lathe. A polycrystalline diamond cutting tool (average grain size 1 μm or less) with an R-shaped cutting edge was used. Various R-shaped edges with radii from 2 mm to 50 mm were used, and the cutting pitch was changed from 0.1 mm to 0.4 mm to machine the desired surface shape. The cutting conditions for the supports used in each example and comparative example are shown in Table 3. Supports with a length of 370 mm and a diameter of 30.5 mm were obtained. The obtained support was ultrasonically cleaned in an alkaline solution with pH=11, the alkaline solution was removed with pure water, and then it was left to stand in hot water at 95°C for 90 seconds. After that, it was removed and dried at room temperature to obtain the support.

[0085] <Manufacturing of electrophotographic photoconductors> (Example 1 of manufacturing the lower layer) 100 parts of rutile-type titanium dioxide particles (average primary particle size: 210 nm, JR-405, manufactured by Teika Co., Ltd.) were stirred and mixed with 500 parts of toluene. 3.0 parts of vinyltrimethoxysilane (product name: KBM-1003, manufactured by Shin-Etsu Chemical Co., Ltd.) were added, and the mixture was stirred for 8 hours. Subsequently, the toluene was removed by vacuum distillation, and the mixture was dried at 120°C for 3 hours to obtain rutile-type titanium dioxide particles (metal oxide particles) surface-treated with vinyltrimethoxysilane.

[0086] Furthermore, 19.5 parts of blocked isocyanate (Sumijule BL3175, manufactured by Sumika Bayer Urethane Co., Ltd., 75% solids by mass) and 7.5 parts of butyral resin (Eslec BL-1, manufactured by Sekisui Chemical Co., Ltd.) were dissolved in 130 parts of methyl ethyl ketone as curing agents. Next, 34 parts of pigment orange 43 (manufactured by Tokyo Chemical Industry Co., Ltd.) and 1.0 part of the above-mentioned surface-treated rutile-type titanium dioxide particles were mixed into the above solution and dispersed in a sand mill for 10 hours to obtain a dispersion. To this dispersion, 0.005 parts of bismuth carboxylate (K-KATXK-640, manufactured by King Industries Co., Ltd.) were added to obtain a coating solution for the undercoat layer. This undercoat layer coating solution was immersed and applied onto a support heated to 30°C, and then cured at 160°C for 60 minutes to form an undercoat layer with a thickness of 1.8 μm.

[0087] (Example 2 of manufacturing the lower layer) [Examples of preparation of the compounds represented by the above formulas (A1) and (A2)] Derivatives having the structure of formula (A1) (derivatives of electron-transporting compounds) can be synthesized, for example, using known synthesis methods described in U.S. Patent No. 4,442,193, U.S. Patent No. 4,992,349, U.S. Patent No. 5,468,583, and Chemistry of Materials, Vol. 19, No. 11, 2703-2705 (2007). They can also be synthesized by the reaction of naphthalenetetracarboxylic dianhydride, which can be purchased from Tokyo Chemical Industry Co., Ltd., Sigma-Aldrich Japan Ltd., and Johnson Matthey Japan, Incorporated, with monoamine derivatives.

[0088] The compound represented by formula (A1) has polymerizable functional groups (hydroxyl group, thiol group, amino group, and carboxyl group) that can polymerize with the isocyanate group of an isocyanate compound. Methods for introducing these substituents to a derivative having the structure of formula (A1) include directly introducing the polymerizable functional group to the derivative having the structure of formula (A1), and introducing a structure having the polymerizable functional group or a functional group that can serve as a precursor to the polymerizable functional group. The methods described below include, for example, introducing a functional group-containing aryl group using a cross-coupling reaction with a palladium catalyst and a base, based on a halide of a naphthylimide derivative; for example, introducing a functional group-containing alkyl group using a cross-coupling reaction with an FeCl3 catalyst and a base, based on a halide of a naphthylimide derivative; and for example, introducing a hydroxyalkyl group or carboxyl group by reacting an epoxy compound or CO2 after lithiation, based on a halide of a naphthylimide derivative. One method for synthesizing naphthylimide derivatives involves using a naphthalenetetracarboxylic dianhydride derivative or monoamine derivative having the polymerizable functional group or a functional group that can serve as a precursor to a polymerizable functional group as a raw material.

[0089] Derivatives having the structure of formula (A2) can be synthesized, for example, using known synthesis methods described in the Journal of the American Chemical Society, Vol. 129, No. 49, 15259-78 (2007). Alternatively, they can be synthesized by the reaction of perylenetetracarboxylic dianhydride, which is available as a reagent from Tokyo Chemical Industry Co., Ltd., Sigma-Aldrich Japan Co., Ltd., and Johnson Matthey Japan, Inc., with a monoamine derivative.

[0090] The compound represented by formula (A2) has a polymerizable functional group (hydroxyl group, thiol group, amino group, and carboxyl group) with the isocyanate group of the isocyanate compound. Methods for introducing these polymerizable functional groups into a derivative having the structure of formula (A2) include directly introducing the polymerizable functional group into the derivative having the structure of formula (A2), and introducing a structure having the polymerizable functional group or a functional group that can serve as a precursor to the polymerizable functional group. One method described later is to use a cross-coupling reaction with a palladium catalyst and a base, based on a halide of a peryleneimide derivative. Another method is to use a cross-coupling reaction with an FeCl3 catalyst and a base, based on a halide of a peryleneimide derivative. Furthermore, when synthesizing peryleneimide derivatives, one can use a perylenetetracarboxylic dianhydride derivative or monoamine derivative having the polymerizable functional group or a functional group that can serve as a precursor to the polymerizable functional group as a raw material.

[0091] A synthesis example is shown below. To 200 parts of dimethylacetamide, 5.4 parts of naphthalenetetracarboxylic dianhydride, 4 parts of 2-methyl-6-ethylaniline, and 3 parts of 2-amino-1-butanol were added under a nitrogen atmosphere, and the mixture was stirred at room temperature for 1 hour to prepare a solution. After preparing the solution, the mixture was refluxed for 8 hours, the precipitate was filtered off, and recrystallization was performed with ethyl acetate to obtain 1.0 part of compound A101.

[0092] Next, 3.11 parts of compound (A154) as an electron transport compound, 0.40 parts of styrene-acrylic resin (product name: UC-3920, manufactured by Toagosei Co., Ltd.), 0.4 parts of polyvinyl butyral resin (product name: BX-1, manufactured by Sekisui Chemical Co., Ltd.), and 6.49 parts of blocked isocyanate compound (product name: SBB-70P, manufactured by Asahi Kasei Co., Ltd.) were dissolved in a mixed solvent of 48 parts 1-butanol and 24 parts acetone. To this solution, a solution of 0.25 parts of compound (α1) (manufactured by Tokyo Chemical Industry Co., Ltd.) dissolved in 6 parts tetrahydrofuran was added, and the mixture was stirred for 1 hour. After that, the mixture was filtered under pressure using an ADVANTEC Teflon® filter (product name: PF020). The obtained undercoat coating solution was immersed and applied onto a support at a temperature of 30°C, and then cured at 170°C for 40 minutes. By curing (polymerizing) the resulting coating film, an undercoat layer with a thickness of 1.8 μm was formed on the support.

[0093] (Example of manufacturing process after the photosensitive layer) 20 parts of hydroxygallium phthalocyanine crystals (charge-generating material) in a crystalline form having peaks at 7.4° and 28.2° of the Bragg angle 2θ±0.2° in CuKα characteristic X-ray diffraction, and 0.2 parts of a calixarene compound represented by the following formula (P). [ka] Ten parts of polyvinyl butyral (product name: S-Rec BX-1, manufactured by Sekisui Chemical Co., Ltd.) and 600 parts of cyclohexanone were placed in a sand mill using 1 mm diameter glass beads and dispersed for 4 hours. Subsequently, 700 parts of ethyl acetate were added to prepare a coating solution for the charge generation layer. This coating solution for the charge generation layer was applied by immersion onto the above-mentioned undercoat layer, and the resulting coating film was dried at 80°C for 15 minutes to form a charge generation layer with a thickness of 0.17 μm.

[0094] Next, 30 parts of the compound represented by formula (Q) below (charge transport material), 60 parts of the compound represented by formula (R) below (charge transport material), and 10 parts of the compound represented by formula (S) below (charge transport material), [ka] [ka] [ka] In addition, 100 parts of polycarbonate resin (product name: Yupiron Z400, manufactured by Mitsubishi Engineering Plastics Corporation, bisphenol Z type polycarbonate) and 0.02 parts of polycarbonate resin represented by the following formula (T) (viscosity-average molecular weight Mv: 20000) [ka] (In equation (T), 0.95 and 0.05 are the molar ratios (copolymerization ratios) of the two units.) A coating solution for the charge transport layer was prepared by dissolving it in a mixed solvent of 600 parts xylene and 200 parts dimethoxymethane. This coating solution for the charge transport layer was applied to the charge generating layer by immersion to form a coating film, and the resulting coating film was dried at 100°C for 30 minutes to form a charge transport layer with a thickness of 18 μm.

[0095] Next, a mixed solvent of 20 parts 1,1,2,2,3,3,4-heptafluorocyclopentane (product name: Zeolora H, manufactured by Nippon Zeon Co., Ltd.) and 20 parts 1-propanol was filtered through a polyflon filter (product name: PF-040, manufactured by Advantec Toyo Co., Ltd.). 90 parts of a hole-transporting compound represented by the following formula (U), [ka] 70 parts of 1,1,2,2,3,3,4-heptafluorocyclopentane and 70 parts of 1-propanol were added to the above mixed solvent. This was filtered through a polyflon filter (product name: PF-020, manufactured by Advantec Toyo) to prepare a coating solution for the second charge transport layer (protective layer). This coating solution for the second charge transport layer was applied to the above charge transport layer by immersion, and the resulting coating film was dried in air at 50°C for 6 minutes. Subsequently, the coating film was irradiated with an electron beam for 1.6 seconds under the conditions of an accelerating voltage of 70kV and an absorbed dose of 8000Gy while rotating the support (irradiated object) at 200 rpm in nitrogen. Subsequently, the coating film was heated in nitrogen from 25°C to 125°C over 30 seconds. The oxygen concentration in the atmosphere during electron beam irradiation and subsequent heating was 15 ppm. Next, a second charge transport layer (protective layer) with a thickness of 5 μm, hardened by electron beam, was formed by heat treatment at 100°C for 30 minutes in air.

[0096] Next, linear grooves were formed on the surface of the protective layer using an abrasive sheet (product name: GC3000, manufactured by Riken Corundum). The feed speed of the abrasive sheet was set to 40 mm / min, the rotation speed of the workpiece to 240 rpm, and the pressure of the abrasive sheet against the workpiece to 7.5 N / m 2 The feeding direction of the abrasive sheet and the rotation direction of the workpiece were set to be the same. In addition, a backup roller with an outer diameter of 40 cm and an Asker C hardness of 40 was used. Under these conditions, linear grooves were formed on the circumferential surface of the workpiece over a period of 10 seconds.

[0097] (Examples 1-18) and (Comparative Examples 1-4) Using a support processed under the cutting conditions described in Table 3, a base layer was formed directly on top of the support using the method described in (Example 1 of base layer production). The surface roughness measurement results of the base layer are shown in Table 3.

[0098] After forming an undercoat on the support, the photosensitive layer and subsequent layers were manufactured using the method described in (Example of manufacturing after the photosensitive layer), and three photoreceptors for each example were obtained. Each of the three obtained photoreceptors was evaluated using the following method.

[0099] [Table 3]

[0100] (Evaluation of surface roughness) A surface roughness meter (product name: SE700, manufactured by Kosaka Laboratory Co., Ltd.) was used to measure surface roughness. The stylus was a cone with a spherical tip, a tip radius of 2 μm, a cone taper angle of 60°, and a measuring force of 0.75 mN. Measurements were performed under the following conditions: cutoff value and evaluation length of 0.8 mm, measurement length of 4.0 mm, and data interval of 1.6 μm. From the measured roughness curve, the maximum height Rz, average height Rc, and average length RSm were calculated according to JIS B 0601:2001. Measurements were taken at the locations shown in Figure 4 (three locations in the generatrix direction: the center and at 1 / 8 of the total length from the end; and four locations in the circumferential direction, approximately every 90 degrees). The average of these 12 measurements was used as the measurement value for the photoreceptor. The average of the three manufactured photoreceptors was used as the measurement value for the example and comparative example. The results are shown in Table 3.

[0101] (Evaluation of interference fringes) (Image evaluation) The manufactured photoreceptor was mounted in the cyan station of an electrophotographic device (copier) (product name: imagePRESSC910, manufactured by Canon Inc., using a 680nm wavelength laser for image exposure) and evaluated in a low-humidity environment (20°C / 10%RH) as follows. Halftone images were printed on A4-sized plain paper with a dark area potential of 800V and a bright area potential of 300V, and the presence or absence of interference fringes on the halftone images was visually confirmed. Based on visual inspection, if no interference fringes were found in any of the three manufactured units, they were deemed acceptable (○). If interference fringes were found in even one unit, they were deemed unacceptable (×). The results are shown in Table 3.

[0102] (Spectroscopic measurement) Using the MCPD-2000 manufactured by Otsuka Electronics Co., Ltd., the manufactured photoreceptor was exposed to light, and the spectral distribution of the reflected light was measured. In photoreceptors where interference fringes are observed, a wave-like spectral distribution is observed in the reflected light, making it possible to quantify the degree of interference fringes.

[0103] The method for measuring the spectral spectrum is described below. A tube made of the same aluminum alloy as the support material, with the same dimensions as the support material (length 370 mm, diameter 30.5 mm), was prepared with a mirror-finished surface. The reflectance of this tube was adjusted to 100% within the measurable wavelength range, and the raw tube was replaced with a photoreceptor under these conditions. The spectral spectrum of the reflected light was then measured. The difference between the maximum and minimum reflectance values ​​was determined in the range of 680 ± 10 nm near the image exposure wavelength. Measurements were taken at 12 locations, the same locations as the surface roughness measurement locations described above, and the average value of these 12 locations was used as the measurement value for the photoreceptor. The average value of the three manufactured photoreceptors was used as the measurement value for the example and comparative example.

[0104] Then, for the photoreceptors that passed the interference fringe image evaluation, the results of the spectral measurements were ranked according to the following criteria. Less than 1.0% ···4 1.0% or more, less than 1.5%...3 1.5% or more, less than 2.0%...2 2.0% or more ···1 The results are shown in Table 3.

[0105] (White dot rating) The manufactured photoreceptor was mounted in the cyan station of an electrophotographic device (copier) (product name: imagePRESSC910, manufactured by Canon Inc., using a 680nm wavelength laser for image exposure) and evaluated in a low-humidity environment (20°C / 10%RH) as follows.

[0106] A solid color image was printed on A4-sized plain paper with a dark area potential of 800V and a bright area potential of 300V. The number and size of white dots in the area corresponding to one full circle of the photoreceptor on the resulting solid color image were then checked, and the area was calculated as number × size = area.

[0107] Image verification was performed after continuously printing 200,000 copies of the initial image and the image with a print ratio of 2% on A4 plain paper. The area of ​​the white dots in each image was then compared to calculate the rate of increase. The results of the growth rate were then ranked according to the following criteria. Less than 15% ···5 15% or more, less than 20%...4 20% or more, less than 25%...3 25% or more, less than 30%...2 30% or more ···1 The results are shown in Table 3.

[0108] (comprehensive evaluation) The evaluation was based on the sum of the rank of the photoreceptor's spectral distribution (in which no interference fringes were observed in the halftone image) and the rank of the white dot evaluation before and after continuous printing in a low-humidity environment. A higher number indicates better performance.

[0109] (Examples 2-18) and (Comparative Examples 1-4) Using a support processed under the cutting conditions described in Table 3, a base layer was formed directly on top of the support using the method described in (Example 1 of base layer production). The surface roughness measurement results of the base layer are shown in Table 3. After forming an undercoat on the support, the photosensitive layer and subsequent layers were manufactured using the method described in (Example of manufacturing after the photosensitive layer), yielding three photoreceptors for each example and comparative example. The conditions were the same as in Example 1, except for the cutting conditions of the support. The results are shown in Table 3.

[0110] (Example 19) Compared to Example 1, where Rc / Rz = 70%, the support temperature during the undercoat manufacturing process was increased by 10°C to 40°C. The surface roughness of the undercoat was measured to be Rc / Rz = 85%. Except for the support temperature being 40°C during undercoat manufacturing, the procedure was the same as in Example 1. The results are shown in Table 3.

[0111] (Example 20) The content of metal oxide particles in the undercoat layer of Example 1 was halved. All other aspects remained the same as in Example 1. The results are shown in Table 3.

[0112] (Example 21) 0.9 parts of the compound shown in formula (V) below were added to the undercoat coating solution of Example 1. All other conditions were the same as in Example 1. The results are shown in Table 3. [ka]

[0113] (Comparative Example 5) Compared to Example 1, where Rc / Rz = 70%, the support temperature during the undercoat manufacturing process was lowered by 10°C to 20°C. The surface roughness of the undercoat was measured to be Rc / Rz = 50%. Except for the support temperature being 20°C during undercoat manufacturing, the procedure was the same as in Example 1. The results are shown in Table 3.

[0114] (Comparative Example 6) In the manufacturing of the undercoat layer in Example 1, the content of metal oxide particles was doubled. Otherwise, the process was the same as in Example 1. The results are shown in Table 3.

[0115] (Examples 22-39) and (Comparative Examples 7-10) Using a support processed under the cutting conditions described in Table 3, a base layer was formed directly on top of the support using the method described in (Example 2 of base layer production). The surface roughness measurement results of the base layer are shown in Table 3. After forming an undercoat on the support, the photosensitive layer and subsequent layers were manufactured using the method described in (Example of manufacturing after the photosensitive layer), yielding three photoreceptors for each example. Except for the cutting conditions of the support, the procedure was the same as in Example 1. The results are shown in Table 3.

[0116] (Example 40) Compared to Example 22, where Rc / Rz = 70%, the support temperature during the undercoat manufacturing process was increased by 10°C to 40°C. The surface roughness of the undercoat was measured to be Rc / Rz = 85%. Except for the support temperature being 40°C during undercoat manufacturing, the procedure was the same as in Example 22. The results are shown in Table 3.

[0117] (Example 41) The amount of compound (α1) added to the coating solution for the undercoat layer was changed from 0.25 parts in Example 22 (compound (α1) content was 8.0% by mass relative to compound (A154)) to 0.06 parts (compound (α1) and compound (A154) were combined to 1.9% by mass). Except for the change in the amount of compound (α1) added, the procedure was the same as in Example 22. The results are shown in Table 3.

[0118] (Example 42) The amount of compound (α1) added to the coating solution for the undercoat layer was changed to 0.11 parts (compound (α1) content of 3.5% by mass relative to compound (A154)) compared to 0.25 parts in Example 22. Except for the change in the amount of compound (α1) added, the procedure was the same as in Example 22. The results are shown in Table 3.

[0119] (Example 43) The amount of compound (α1) added to the coating solution for the undercoat layer was changed from 0.25 parts in Example 22 to 0.47 parts (compound (α1) content was 15.1% by mass relative to compound (A154)). Except for the change in the amount of compound (α1) added, the procedure was the same as in Example 22. The results are shown in Table 3.

[0120] (Example 44) The amount of compound (α1) added to the coating solution for the undercoat layer was changed from 0.25 parts in Example 22 to 0.55 parts (compound (α1) content of 17.5% by mass relative to compound (A154)). Except for the change in the amount of compound (α1) added, the procedure was the same as in Example 22. The results are shown in Table 3.

[0121] (Example 45) In Example 22, compound (α1) was not added to the coating solution for the undercoat layer. Otherwise, the procedure was the same as in Example 22. The results are shown in Table 3.

[0122] (Comparative Example 11) Compared to Example 22, where Rc / Rz = 70%, the support temperature during the undercoat manufacturing process was lowered by 10°C to 20°C. The surface roughness of the undercoat was measured to be Rc / Rz = 50%. Except for the support temperature being 20°C during undercoat manufacturing, the procedure was the same as in Example 22. The results are shown in Table 3.

[0123] The disclosure of embodiments according to the present invention includes the following configurations and methods. (Composition 1) In an electrophotographic photoreceptor having a cylindrical support, an undercoat formed directly above the support, and a photosensitive layer formed directly above the undercoat, wherein the undercoat contains a cured product of a composition containing an electron-transporting compound, when the maximum height of the roughness curve of the surface of the undercoat in the generatrix direction of the support, as defined in JIS B 0601:2001, is Rz, the average height is Rc, and the average length is RSm, 0.3 μm ≤ Rz ≤ 1.0 μm Rc / Rz≧70% 0.17mm≦RSm≦0.35mm An electrophotographic photoreceptor characterized by satisfying the following conditions. (Configuration 2) The average length RSm is, 0.17mm ≤ RSm ≤ 0.34mm An electrophotographic photoreceptor as described in configuration 1, which satisfies the requirements. (Composition 3) The average length RSm is, 0.20mm ≤ RSm ≤ 0.30mm An electrophotographic photoreceptor according to configuration 1 or 2 that satisfies the requirements. (Composition 4) The electrophotographic photoreceptor according to configurations 1 to 3, wherein the undercoat contains metal oxide particles, and the content of the metal oxide particles relative to the total solid content of the undercoat is 1.0% by mass or less. (Composition 5) The aforementioned undercoat layer is an electrophotographic photoreceptor according to configurations 1 to 3, which does not contain metal oxide particles. (Composition 6) The electron-transporting compound is an electrophotographic photoreceptor according to configurations 1 to 5, represented by the following formula (A1) or (A2). [ka] (In formulas (A1) and (A2), R 101 ~R 106 , R 201 ~R 210Each of these independently represents a monovalent group, a hydrogen atom, a cyano group, a nitro group, a halogen atom, an alkoxycarbonyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group represented by the following formula (B). However, R 101 ~R 106 At least one of the following, and R 201 ~R 210 At least one of the groups is a monovalent group represented by the following formula (B). One of the CH2 groups of the alkyl group may be substituted with O or S, or one of the CH groups of the alkyl group may be substituted with N. The substituent of the substituted alkyl group is at least one group selected from the group consisting of aryl groups, alkoxycarbonyl groups, halogen atoms, and hydroxyl groups. The substituent of the substituted aryl group and the substituted heterocycle is at least one group selected from the group consisting of halogen atoms, nitro groups, cyano groups, alkyl groups, halogen-substituted alkyl groups, and alkoxy groups. [ka] (In formula (B), at least one of a, b, and c has at least one group selected from the group consisting of a hydroxyl group, a thiol group, an amino group, and a carboxyl group. l and m are each independently 0 or 1, and the sum of l and m is between 0 and 2.) a represents an alkylene group having 1 to 6 carbon atoms in the main chain, an alkylene group having 1 to 6 carbon atoms in the main chain substituted with an alkyl group having 1 to 6 carbon atoms, an alkylene group having 1 to 6 carbon atoms in the main chain substituted with a benzyl group, an alkylene group having 1 to 6 carbon atoms in the main chain substituted with an alkylocarbonyl group, or an alkylene group having 1 to 6 carbon atoms in the main chain substituted with a phenyl group. These alkylene groups may have at least one substituent selected from the group consisting of a hydroxyl group, a thiol group, an amino group, and a carboxyl group. One of the CH2s in the main chain of these alkylene groups may be substituted with O or S, or one of the CHs in the main chain of these alkylene groups may be substituted with N. b represents a phenylene group, a C1-C6 alkyl-substituted phenylene group, a nitro-substituted phenylene group, a halogen-substituted phenylene group, or an alkoxy-substituted phenylene group, and these phenylene groups may have at least one substituent selected from the group consisting of a hydroxyl group, a thiol group, an amino group, and a carboxyl group. c represents a hydrogen atom, a carboxyl group, an alkyl group with 1 to 6 carbon atoms in the main chain, or an alkyl group with 1 to 6 carbon atoms in the main chain substituted with an alkyl group with 1 to 5 carbon atoms. These alkyl groups may have at least one substituent selected from the group consisting of a hydroxyl group, a thiol group, an amino group, and a carboxyl group. (Composition 7) The electrophotographic photoreceptor according to configurations 1 to 6, wherein the undercoat layer comprises a compound represented by the following formula (α). [ka] (In equation (α), Ar 1 and Ar 2 Each independently represents a substituted or unsubstituted phenyl group. The substituent is an alkyl group or an alkoxy group. 3 (where n is an n-valent aromatic group, and n is an integer between 1 and 3.) (Composition 8) The electrophotographic photoreceptor according to configuration 7, wherein the content of compound (α) is 3.5% by mass or more and 15.0% by mass or less relative to the compound represented by formula (A1) or formula (A2). (Method 1) A method for manufacturing an electrophotographic photoreceptor having a cylindrical support, an undercoat formed directly on the support, and a photosensitive layer formed directly on the undercoat, comprising the steps of cutting the surface of the support and applying a liquid containing a cured product of a composition containing an electron transport compound to the surface of the support to form a coating film, wherein the surface of the undercoat is such that, when the maximum height of the roughness curve in the generatrix direction of the support is Rz, the average height is Rc, and the average length is RSm as defined in JIS B 0601:2001, 0.3 μm ≤ Rz ≤ 1.0 μm Rc / Rz ≥ 70% 0.17mm ≤ RSm ≤ 0.35mm A method for manufacturing an electrophotographic photoreceptor, comprising the step of forming an undercoat layer that satisfies certain conditions. (Composition 9) A process cartridge that integrally supports an electrophotographic photoreceptor as described in any one of configurations 1 to 8, and at least one means selected from the group consisting of a charging means, a developing means, and a cleaning means, and is detachably attached to the main body of an electrophotographic apparatus. (Composition 10) An electrophotographic apparatus comprising an electrophotographic photoreceptor as described in any one of items 1 to 8, and a charging means, an exposure means, a developing means, and a transfer means. [Explanation of symbols]

[0124] 100, 301... Electrophotographic photoreceptor 101‥‥Support 102... Surface of the support 103... Lower layer 104... Surface of the undercoat 105‥‥Photosensitive layer 106...Charge generation layer 107‥‥Charge transport layer 108... Surface of the electrophotographic photoreceptor

Claims

1. In an electrophotographic photoreceptor having a cylindrical support, an undercoat formed directly above the support, and a photosensitive layer formed directly above the undercoat, wherein the undercoat contains a cured product of a composition containing an electron-transporting compound, when the maximum height of the roughness curve of the surface of the undercoat in the generatrix direction of the support, as defined in JIS B 0601:2001, is Rz, the average height is Rc, and the average length is RSm, 0.3μm≦Rz≦1.0μm Rc / Rz ≥ 70% 0.17mm≦RSm≦0.35mm An electrophotographic photoreceptor characterized by satisfying the following conditions.

2. The average length RSm is, 0.17mm≦RSm≦0.34mm An electrophotographic photoreceptor according to claim 1 that satisfies the requirements.

3. The average length RSm is, 0.20mm≦RSm≦0.30mm An electrophotographic photoreceptor according to claim 1 that satisfies the requirements.

4. The electrophotographic photoreceptor according to claim 1, wherein the undercoat contains metal oxide particles, and the content of the metal oxide particles relative to the total solid content of the undercoat is 1.0% by mass or less.

5. The electrophotographic photoreceptor according to claim 1, wherein the undercoat layer does not contain metal oxide particles.

6. The electrophotographic photoreceptor according to claim 1, wherein the electron-transporting compound is represented by the following formula (A1) or (A2). 【Chemistry 1】 (In formulas (A1) and (A2), R １０１ to R １０６ , R ２０１ to R ２１０ each independently represent a monovalent group represented by the following formula (B), a hydrogen atom, a cyano group, a nitro group, a halogen atom, an alkoxycarbonyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group; provided that R １０１ to R １０６ at least one of, and R ２０１ to R ２１０ at least one of is a monovalent group represented by the following formula (B). One CH ２ in the alkyl group may be substituted with O or S, or one CH in the alkyl group may be substituted with N. The substituent of the substituted alkyl group is at least one group selected from the group consisting of aryl groups, alkoxycarbonyl groups, halogen atoms and hydroxy groups. The substituent of the substituted aryl group and the substituted heterocyclic group is at least one group selected from the group consisting of halogen atoms, nitro groups, cyano groups, alkyl groups, halogen-substituted alkyl groups, and alkoxy groups.) 【Chemistry 2】 (In formula (B), at least one of a, b, and c has at least one group selected from the group consisting of a hydroxyl group, a thiol group, an amino group, and a carboxyl group. l and m are each independently 0 or 1, and the sum of l and m is 0 or greater and 2 or less.) a represents an alkylene group having 1 to 6 carbon atoms in the main chain, an alkylene group having 1 to 6 carbon atoms in the main chain substituted with an alkyl group having 1 to 6 carbon atoms, an alkylene group having 1 to 6 carbon atoms in the main chain substituted with a benzyl group, an alkylene group having 1 to 6 carbon atoms in the main chain substituted with an alkylcarbonyl group, or an alkylene group having 1 to 6 carbon atoms in the main chain substituted with a phenyl group. These alkylene groups may have at least one substituent selected from the group consisting of a hydroxyl group, a thiol group, an amino group, and a carboxyl group. CH in the main chain of these alkylene groups ２ One of these groups may be substituted with O or S, or one of the CH groups in the main chain of these alkylene groups may be substituted with N. b represents a phenylene group, a C1-C6 alkyl-substituted phenylene group, a nitro-substituted phenylene group, a halogen-substituted phenylene group, or an alkoxy-substituted phenylene group. These phenylene groups may have at least one substituent selected from the group consisting of a hydroxyl group, a thiol group, an amino group, and a carboxyl group. c represents a hydrogen atom, a carboxyl group, an alkyl group with 1 to 6 carbon atoms in the main chain, or an alkyl group with 1 to 6 carbon atoms in the main chain substituted with an alkyl group with 1 to 5 carbon atoms. These alkyl groups may have at least one substituent selected from the group consisting of a hydroxyl group, a thiol group, an amino group, and a carboxyl group.

7. The electrophotographic photoreceptor according to claim 6, wherein the undercoat layer comprises a compound represented by the following formula (α). 【Transformation 3】 (In equation (α), Ar １ and Ar ２ Each independently represents a substituted or unsubstituted phenyl group. The substituent is an alkyl group or an alkoxy group. Ar ３ (where n is an integer between 1 and 3, where n is an n-valent aromatic group.)

8. The electrophotographic photoreceptor according to claim 7, wherein the content of compound (α) is 3.5% by mass or more and 15.0% by mass or less relative to the compound represented by formula (A1) or formula (A2).

9. A method for manufacturing an electrophotographic photoreceptor having a cylindrical support, an undercoat formed directly above the support, and a photosensitive layer formed directly above the undercoat, comprising the steps of: cutting the surface of the support; and applying a liquid containing a cured product of a composition containing an electron-transporting compound to the surface of the support to form a coating film, wherein the surface of the undercoat is such that, when the maximum height of the roughness curve defined in JIS B 0601:2001 in the generatrix direction of the support is Rz, the average height is Rc, and the average length is RSm, 0.3μm≦Rz≦1.0μm Rc / Rz ≥ 70% 0.17mm≦RSm≦0.35mm A method for manufacturing an electrophotographic photoreceptor, comprising the step of forming an undercoat layer that satisfies certain conditions.

10. A process cartridge that integrally supports an electrophotographic photoreceptor according to any one of claims 1 to 8 and at least one means selected from the group consisting of a charging means, a developing means, and a cleaning means, and is detachably attached to the body of an electrophotographic apparatus.

11. An electrophotographic photoreceptor according to any one of claims 1 to 8, and an electrophotographic apparatus having a charging means, an exposure means, a developing means, and a transfer means.

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